Field of the Invention
The present invention relates to a drive control technique for a moving object such as the carriage of a serial printing apparatus.
Description of the Related Art
In a serial printer, motor drive of a carriage that is reciprocally moved by a motor is generally feedback control such as PID control using an encoder. At this time, there is known control of resolving the influence of the variation of the torque of a DC motor.
In motor drive control disclosed in Japanese Patent Laid-Open No. 2011-230365, a signal generator generates a signal having periodicity, and the periodical parameter of the cogging torque is extracted in advance prior to a print operation. A periodical vibration is detected from the obtained velocity variation amount of the carriage. A voltage correction value (cancel signal) to be applied in a direction in which the periodical vibration caused by the cogging torque is canceled is calculated to perform drive control of the carriage at the time of printing.
In this specification, feedforward control of canceling a cogging torque by predictively adding a vibration suppression value based on preliminary information will be called “cogging cancel control” hereinafter.
The cogging cancel control disclosed in Japanese Patent Laid-Open No. 2011-230365 requires a step of detecting a cogging torque in advance prior to carriage drive for printing in order to generate a cancel signal. This detection takes a long time, is an overhead other than a real print operation, and hinders the improvement of the total print throughput. How to reduce this overhead is a problem to be solved.